General view

The former official residence of the prince-bishops of Mainz, Schloss Johannisburg is one of the most splendid examples of German castle construction during the Renaissance and Baroque eras. The original medieval citadel (c. 1100-c. 1400) was almost completely destroyed in 1552 during the second Margrave war; only the 14th-century donjon survived. The new castle was built on the same site, and derived its name from the citadel chapel of St John the Baptist. In 1605 Johann Schweikart von Kronberg, Archbishop and Elector of Mainz (reg 1604-26), summoned Georg Riedinger to Aschaffenburg to plan and supervise the castle reconstruction. Work began in February 1614 and was completed nine years later at the enormous cost of one million guilders.

Riedinger's scheme consists of four long ranges, each 51 m in length and three storeys high to the eaves, disposed around a square inner courtyard. In planning Schloss Johannisburg, Riedinger used as his basis the main dimensions of the medieval donjon, which he incorporated in the north range of his new building as a symbol of tradition and the continuity of power and dominion exercised by the prince-bishops.

The four corner towers on the exterior of Schloss Johannisburg have eight storeys and are 52 m high; the smaller stair-towers on the interior of the corners have four storeys and rise above a square ground floor into an octagon. With the exception of the stuccoed walls of the donjon, the elevations are faced in uniform courses of red sandstone ashlar. The quoins of the corps de logis are emphasized by diamond faceting. The three storeys, treated almost identically, are articulated horizontally by powerful string courses that also run round the towers, and vertically by axially located windows that have distinctive jambs and are capped by pediments that vary according to floor. Apart from the northern range with its towering donjon, the other three façades are richly ornamented, displaying decorative forms of the German Renaissance as well as Italian influences.

In the late 16th and early 17th centuries, influenced by French and Italian architectural theory, several other buildings with a similar plan were built in south-western Germany, especially in the Roman Catholic territories.

Schloss Johannisburg was severely damaged in World War II, but between 1954 and 1964 the exterior and chapel were restored following the 17th-century model.

View the ground plan of the castle.